         (recur (inc n) F)))))
 
 (defn m [ds i j D]
-  (let [v (v ds i j D), r (r ds i j D)]
+  (let [v (v ds i j D)
+        r (r ds i j D)]
     (when (and v r) (* v r))))
 
 (defn chain-end [ds D i j]

              (/ (s D) (v D)))))
  ([ds]
    (curvature ds 0)))

                      (ops ds)
                      (vs ds))
                w))

(defn walk [ds D & idxs]
  "Returns the result of applying the D-symbol operators on ds with the
